Model Train Scale and Gauge
By Joan Whetzel
Model trains come in a variety of sizes. The size you choose depends on how much room you have to set up a train set, the size of trains and track you can handle comfortably, and how much money you can afford to spend. Some trains are great for families with kids - G gauge, for instance have large trains that are easy for small kids to handle, however they take up massive amounts of space. Others, like N and Z scale take up very little space and make use of extremely tiny scenery items, but are not ideal for small children. Indeed, the scenery items and even the train cars can become choking hazards.
There's a lot to consider when looking at buying a train set. The main thing to look at is scale and gauge, which help determine the size of the trains, scenery and layouts. The individual gauges and scales are set up to be scale replicas of their prototypes, the real world trains.
Scale for model trains is a ratio (the relationship between the model's size and the size of the real world counterparts they were modeled after). If the prototype (real world) item is 1 foot (12 inches) long and the model replica is 1 inch long, then the model is 1/12 or 1:12 scale, because the model is 12 times smaller than the real thing. Lionel trains are said to be 1/48 or 1:48 scale, making the sets and accessories approximately 48 times smaller than their real world counterparts.
Gauge, on the other hand, measures the spacing between the rails on the model train track. All track gauge - on real world and model train tracks alike - measures gauge (rail spacing) between the inner sides of the rails, the sides of the two rails that face each other. The one exception to this rule is with Lionel 3-rail track. This style of track has three rails instead of the usual two. In this case, the rail gauge is measured between the center line of the outer two rails. Each of the model train gauges is given a letter code to identify it - G, O (Lionel), S, HO, OO, HO, TT, N and Z.
Scale / Gauge Relationship
The following descriptions show the relationship between the scale and gauge for each size of model train.
· G-gauge train scale is 1:24 (1/24) and has a rail spacing of 1.75 inches (approximately 45 mm).
· O-gauge (Lionel trains) is 1:48 (1/48) scale and has rail spacing of 2.125 inches (54 mm).
· S-gauge has a 1:64 (1/64) scale and rail gauge of 0.875 inches (22.4 mm).
· OO-gauge has a 1:76 scale and a rail gauge of 0.750 inches (19.1 mm).
· HO trains have a 1:87.1 scale and a rail gauge of 0.650 inches (16.5 mm).
· TT trains have a scale of 1:120 and rail gauge of 0.472 inches (12 mm).
· N trains have a 1:160 scale and a rail gauge of 0.345 inches (9 mm).
· And finally, Z trains have a scale of 1:220 and a rail gauge of 0.246 inches (5.99 mm).
You can see that as the scale of the trains gets smaller so does the spacing between the track rails. The gauge ranges from 1 3/4 inch between the rails on G-scale trains all the way down to less than 1/4 inch on the extremely tiny Z-scale trains. The O scale tracks are not 1:48 scale. The exact scale would give a track gauge of 1.1223958, a number that's too difficult to work with, so the track gauge was changed to 1:43 scale to a more easily workable spacing of 11/4 inch spacing.
Many major cities in the US have train clubs that run large club layouts. Some of the clubs have permanent layouts that are open to the public during set hours. Most of the clubs have portable layouts that they transport to train shows and meets. These train shows are open to the public for a nominal fee at the gate. Once inside these portable layouts are set and run for public viewing. Multitudes of vendors also sell their wares; anything from model train sets, track and scenery to books, videos, and collectible items from the heyday of passenger train travel (includes company stocks, china, photos, etc.). If you're really into trains, it's worth looking up the local train clubs and investigating train shows near you.
Check out these Houston Area Train Clubs
If you're in Houston, or just visiting, look up the following area train clubs. Included is the mailing address and website for each club. Houston Tinplate Operators Society (Lionel trains) has a storefront club house that's open to the public on Tuesday evenings and Saturdayafternoons.
Houston Tinplate Operators Society (HTOS)
Houston Tinplate Operators Society, Inc.
11152 Westheimer #255
Houston, Texas 77042
HTOS Storefront Location:
Memorial City Mall
9955 Katy Fwy, # 233
Houston Area "G" Gaugers
c/o C. Blumentritt
18210 Forest Town Dr
Houston TX 77084
Houston N Crowd
N'Crowd Model Railroad Society
4633 Hummingbird St.
Houston, Texas 77035-5125
All Points North Model Railroading Club (HO)
611 South Magnolia Drive
Conroe, TX 77301